The top “super PACs’’ supporting Republicans in the fall elections have raised more than three times as much money as super PACs aligned with Democrats, $158 million to $47 million, a Globe analysis shows.

The imbalance comes as well-to-do Republicans have been far more generous than their Democratic counterparts, more frequently tossing as much as $1 million or more into the GOP cause.

Unless things change in the next four months, the gap could cost the Democrats the White House and both houses of Congress, no less an authority than President Obama said in a conference call to major Democratic donors late last week.

The president urged his top funders to step up their efforts in a system of campaign finance that permits corporations, labor unions, and individuals to give unlimited amounts to super PACs, which spend independently of candidates and parties.

Thus far, big Republican funders have dominated the show. At the end of May, Casino tycoon Sheldon Adelson and his wife, Miriam, had already contributed $20 million to super PACs supporting a Republican Congress and failed GOP presidential hopeful Newt Gingrich.
Published reports have said Adelson gave a super PAC supporting presumptive GOP nominee Mitt Romney another $10 million, an amount not included in the Globe’s overall totals because it has not yet been officially reported to the Federal Election Commission.

Another Republican billionaire, Harold Simmons, his Texas-based chemicals and metals conglomerate Contran Corp., and his wife, Annette, have given a combined $18.3 million to a total of nine GOP-allied super PACs, Federal Election Commission records show.

By contrast, DreamWorks Animation CEO Jeffrey Katzenberg is the leading individual Democratic donor, having given $2.1 million to two pro-Democrat super PACs.

Beyond the sheer volume from some donors, the imbalance also is reflected in the number of individual entities making jumbo donations. At least 35 individuals and corporations had donated $1 million or more to Republican super PACs, compared with 16 (including seven labor unions) to Democratic groups.

The lopsided pattern also appears in the marquee presidential contest. Restore Our Future, the super PAC supporting presumptive Republican nominee Mitt Romney, had taken in $61.5 million, more than four times the $14.6 million raised by Priorities USA Action, the super PAC supporting Obama, through the end of last month.

The race to tap wealthy contributors went into overdrive after 2010 federal court rulings that dramatically loosened campaign finance regulations. Individuals are still limited in how much they can give to candidates’ committees and party committees. But now super PACs are running parallel operations, collecting whatever sums people want to give; they are not supposed to coordinate their spending with candidates.

In his call last week, which the online news site Daily Beast reported after obtaining a recording, Obama told major funders: “We are going to see more money spent on negative ads through these super PACs and anonymous outside groups than ever before. And if things continue as they have so far, I’ll be the first sitting president in modern history to be outspent in his reelection campaign.”

The “anonymous outside” groups Obama referred to are politically active nonprofit organizations, the most active of which are on the Republican side, set up under the tax code to promote “social welfare” and not required to disclose their donors. Super PACs must disclose their contributors.

Republicans say their supporters are kicking in millions in direct response to Obama’s presidency.

“There are conservative donors who are dramatically motivated by the explosion of spending, regulations, and debt under this president, and there is a great desire to put the brakes on his agenda,” said Jonathan Collegio, spokesman for American Crossroads, a muscular GOP super PAC that has attacked Obama and Democrats running for Congress and had raised $34.3 million through the end of May.

Democrats, including the president on his conference call, have said Democrats may be contributing less because they are overconfident the president can beat Romney or they are disillusioned by the slow pace of promised change in Washington. But there also is a deep philosophical objection to the system of unlimited spending that has blossomed since the January 2010 Supreme Court ruling in the Citizens United case, which said corporations and unions could spend as much as they pleased to influence elections. Others don’t want their money to be spent on negative advertising, said Democratic fund-raisers and spokesmen for wealthy donors.

For instance, the only super PAC donation this cycle by Peter Lewis, who made his fortune as head of Progressive Insurance, was $200,000 to American Bridge 21st Century, which specializes in research it shares with Democratic-leaning groups.

“He finds the corrupting power of money offensive with its negativity and denigration of opponents,” Jennifer Frutchy, his spokeswoman, said in an e-mail. He has no other plans to give to super PACs this year, she said, preferring instead “to build progressive infrastructure.”

In the 2004 cycle, Lewis gave $23.2 million to independent groups that supported Democrats, the second most of any individual, according to data compiled by the nonpartisan Center for Responsive Politics.

In some respects, the 2012 money race is a reverse image of 2004, when big Democratic donors, animated by intense opposition to Republican incumbent George W. Bush, heavily outspent rival GOP givers to underwrite expensive field operations and advertising paid for by independent groups. The effort failed to capture the presidency, however, and some Democratic activists believe that failure has dampened enthusiasm this year.

In 2004, of the 24 individuals who gave $2 million or more to independent groups, 14 were Democrats. They donated a combined $109 million compared with $39 million donated by 10 Republicans, according to data from the Center for Responsive Politics.

Billionaire financier George Soros, who led all donors with $23.7 million to independent Democratic groups, in this cycle so far has targeted only about $2.2 million to independent groups, with the lion’s share going to organizations that engage in research or grass-roots liberal advocacy.

“He’s given $1 million each to [America Votes] and [American Bridge 21st Century],” his spokesman, Michael Vachon, said in an e-mail. “As to what he will do in the future, I don’t know.”

Similarly, FEC records show that film producer Stephen Bing, who gave $13.9 million to independent groups supporting Democrats in 2004, has donated $425,000 to super PACs this cycle — $250,000 to Majority PAC, which is trying to elect Democrats to the Senate, $150,000 to American Bridge, and $25,000 to the League of Conservation Voters.

Bing “does not comment on these matters,” Paul Bloch, a spokesman, wrote in an e-mail.